Question

Why does Beryllium have a larger first Ionization energy than boron?

Answer 1

Check the electron configurations, and keep in mind that a full orbital is very stable, and a half-full orbital is the next most stable configuration.

Be: 1s2 2s2
B: 1s2 2s2 2p1

To ionise beryllium, a full orbital has to be disturbed. It will convert from a full orbital to a non-full orbital, which takes a lot of energy, since disturbing a stable configuration is hard.

To ionise boron, all that has to be done is remove an electron from an orbital that is neither full nor half full, meaning the orbital does not have very great stability. Removing the electron will give it full orbitals, allowing it to attain a stable state. This drive towards stability makes it easier to ionise

Answer 2

The first ionization of Beryllium is greater than that of Boron because beryllium has a stable complete electronic configuration(1s2 2s2)so it requires more energy to remove the first electron from it......whereas boron has the electronic configuration(1s2 2s2 3s1)which needs lesser energy than that of beryllium to remove the valence electron.........I think this might help you...